| //! Implementation of lint checking. |
| //! |
| //! The lint checking is mostly consolidated into one pass which runs |
| //! after all other analyses. Throughout compilation, lint warnings |
| //! can be added via the `add_lint` method on the Session structure. This |
| //! requires a span and an ID of the node that the lint is being added to. The |
| //! lint isn't actually emitted at that time because it is unknown what the |
| //! actual lint level at that location is. |
| //! |
| //! To actually emit lint warnings/errors, a separate pass is used. |
| //! A context keeps track of the current state of all lint levels. |
| //! Upon entering a node of the ast which can modify the lint settings, the |
| //! previous lint state is pushed onto a stack and the ast is then recursed |
| //! upon. As the ast is traversed, this keeps track of the current lint level |
| //! for all lint attributes. |
| |
| use crate::context::{EarlyContext, LintContext, LintStore}; |
| use crate::passes::{EarlyLintPass, EarlyLintPassObject}; |
| use rustc_ast::ast; |
| use rustc_ast::visit as ast_visit; |
| use rustc_session::lint::{BufferedEarlyLint, LintBuffer, LintPass}; |
| use rustc_session::Session; |
| use rustc_span::symbol::Ident; |
| use rustc_span::Span; |
| |
| use log::debug; |
| use std::slice; |
| |
| macro_rules! run_early_pass { ($cx:expr, $f:ident, $($args:expr),*) => ({ |
| $cx.pass.$f(&$cx.context, $($args),*); |
| }) } |
| |
| struct EarlyContextAndPass<'a, T: EarlyLintPass> { |
| context: EarlyContext<'a>, |
| pass: T, |
| } |
| |
| impl<'a, T: EarlyLintPass> EarlyContextAndPass<'a, T> { |
| fn check_id(&mut self, id: ast::NodeId) { |
| for early_lint in self.context.buffered.take(id) { |
| let BufferedEarlyLint { span, msg, node_id: _, lint_id, diagnostic } = early_lint; |
| self.context.lookup_with_diagnostics( |
| lint_id.lint, |
| Some(span), |
| |lint| lint.build(&msg).emit(), |
| diagnostic, |
| ); |
| } |
| } |
| |
| /// Merge the lints specified by any lint attributes into the |
| /// current lint context, call the provided function, then reset the |
| /// lints in effect to their previous state. |
| fn with_lint_attrs<F>(&mut self, id: ast::NodeId, attrs: &'a [ast::Attribute], f: F) |
| where |
| F: FnOnce(&mut Self), |
| { |
| let is_crate_node = id == ast::CRATE_NODE_ID; |
| let push = self.context.builder.push(attrs, &self.context.lint_store, is_crate_node); |
| self.check_id(id); |
| self.enter_attrs(attrs); |
| f(self); |
| self.exit_attrs(attrs); |
| self.context.builder.pop(push); |
| } |
| |
| fn enter_attrs(&mut self, attrs: &'a [ast::Attribute]) { |
| debug!("early context: enter_attrs({:?})", attrs); |
| run_early_pass!(self, enter_lint_attrs, attrs); |
| } |
| |
| fn exit_attrs(&mut self, attrs: &'a [ast::Attribute]) { |
| debug!("early context: exit_attrs({:?})", attrs); |
| run_early_pass!(self, exit_lint_attrs, attrs); |
| } |
| } |
| |
| impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T> { |
| fn visit_param(&mut self, param: &'a ast::Param) { |
| self.with_lint_attrs(param.id, ¶m.attrs, |cx| { |
| run_early_pass!(cx, check_param, param); |
| ast_visit::walk_param(cx, param); |
| }); |
| } |
| |
| fn visit_item(&mut self, it: &'a ast::Item) { |
| self.with_lint_attrs(it.id, &it.attrs, |cx| { |
| run_early_pass!(cx, check_item, it); |
| ast_visit::walk_item(cx, it); |
| run_early_pass!(cx, check_item_post, it); |
| }) |
| } |
| |
| fn visit_foreign_item(&mut self, it: &'a ast::ForeignItem) { |
| self.with_lint_attrs(it.id, &it.attrs, |cx| { |
| run_early_pass!(cx, check_foreign_item, it); |
| ast_visit::walk_foreign_item(cx, it); |
| run_early_pass!(cx, check_foreign_item_post, it); |
| }) |
| } |
| |
| fn visit_pat(&mut self, p: &'a ast::Pat) { |
| run_early_pass!(self, check_pat, p); |
| self.check_id(p.id); |
| ast_visit::walk_pat(self, p); |
| run_early_pass!(self, check_pat_post, p); |
| } |
| |
| fn visit_anon_const(&mut self, c: &'a ast::AnonConst) { |
| run_early_pass!(self, check_anon_const, c); |
| ast_visit::walk_anon_const(self, c); |
| } |
| |
| fn visit_expr(&mut self, e: &'a ast::Expr) { |
| self.with_lint_attrs(e.id, &e.attrs, |cx| { |
| run_early_pass!(cx, check_expr, e); |
| ast_visit::walk_expr(cx, e); |
| }) |
| } |
| |
| fn visit_stmt(&mut self, s: &'a ast::Stmt) { |
| run_early_pass!(self, check_stmt, s); |
| self.check_id(s.id); |
| ast_visit::walk_stmt(self, s); |
| } |
| |
| fn visit_fn(&mut self, fk: ast_visit::FnKind<'a>, span: Span, id: ast::NodeId) { |
| run_early_pass!(self, check_fn, fk, span, id); |
| self.check_id(id); |
| ast_visit::walk_fn(self, fk, span); |
| run_early_pass!(self, check_fn_post, fk, span, id); |
| } |
| |
| fn visit_variant_data(&mut self, s: &'a ast::VariantData) { |
| run_early_pass!(self, check_struct_def, s); |
| if let Some(ctor_hir_id) = s.ctor_id() { |
| self.check_id(ctor_hir_id); |
| } |
| ast_visit::walk_struct_def(self, s); |
| run_early_pass!(self, check_struct_def_post, s); |
| } |
| |
| fn visit_struct_field(&mut self, s: &'a ast::StructField) { |
| self.with_lint_attrs(s.id, &s.attrs, |cx| { |
| run_early_pass!(cx, check_struct_field, s); |
| ast_visit::walk_struct_field(cx, s); |
| }) |
| } |
| |
| fn visit_variant(&mut self, v: &'a ast::Variant) { |
| self.with_lint_attrs(v.id, &v.attrs, |cx| { |
| run_early_pass!(cx, check_variant, v); |
| ast_visit::walk_variant(cx, v); |
| run_early_pass!(cx, check_variant_post, v); |
| }) |
| } |
| |
| fn visit_ty(&mut self, t: &'a ast::Ty) { |
| run_early_pass!(self, check_ty, t); |
| self.check_id(t.id); |
| ast_visit::walk_ty(self, t); |
| } |
| |
| fn visit_ident(&mut self, ident: Ident) { |
| run_early_pass!(self, check_ident, ident); |
| } |
| |
| fn visit_mod(&mut self, m: &'a ast::Mod, s: Span, _a: &[ast::Attribute], n: ast::NodeId) { |
| run_early_pass!(self, check_mod, m, s, n); |
| self.check_id(n); |
| ast_visit::walk_mod(self, m); |
| run_early_pass!(self, check_mod_post, m, s, n); |
| } |
| |
| fn visit_local(&mut self, l: &'a ast::Local) { |
| self.with_lint_attrs(l.id, &l.attrs, |cx| { |
| run_early_pass!(cx, check_local, l); |
| ast_visit::walk_local(cx, l); |
| }) |
| } |
| |
| fn visit_block(&mut self, b: &'a ast::Block) { |
| run_early_pass!(self, check_block, b); |
| self.check_id(b.id); |
| ast_visit::walk_block(self, b); |
| run_early_pass!(self, check_block_post, b); |
| } |
| |
| fn visit_arm(&mut self, a: &'a ast::Arm) { |
| run_early_pass!(self, check_arm, a); |
| ast_visit::walk_arm(self, a); |
| } |
| |
| fn visit_expr_post(&mut self, e: &'a ast::Expr) { |
| run_early_pass!(self, check_expr_post, e); |
| } |
| |
| fn visit_generic_param(&mut self, param: &'a ast::GenericParam) { |
| run_early_pass!(self, check_generic_param, param); |
| ast_visit::walk_generic_param(self, param); |
| } |
| |
| fn visit_generics(&mut self, g: &'a ast::Generics) { |
| run_early_pass!(self, check_generics, g); |
| ast_visit::walk_generics(self, g); |
| } |
| |
| fn visit_where_predicate(&mut self, p: &'a ast::WherePredicate) { |
| run_early_pass!(self, check_where_predicate, p); |
| ast_visit::walk_where_predicate(self, p); |
| } |
| |
| fn visit_poly_trait_ref(&mut self, t: &'a ast::PolyTraitRef, m: &'a ast::TraitBoundModifier) { |
| run_early_pass!(self, check_poly_trait_ref, t, m); |
| ast_visit::walk_poly_trait_ref(self, t, m); |
| } |
| |
| fn visit_assoc_item(&mut self, item: &'a ast::AssocItem, ctxt: ast_visit::AssocCtxt) { |
| self.with_lint_attrs(item.id, &item.attrs, |cx| match ctxt { |
| ast_visit::AssocCtxt::Trait => { |
| run_early_pass!(cx, check_trait_item, item); |
| ast_visit::walk_assoc_item(cx, item, ctxt); |
| run_early_pass!(cx, check_trait_item_post, item); |
| } |
| ast_visit::AssocCtxt::Impl => { |
| run_early_pass!(cx, check_impl_item, item); |
| ast_visit::walk_assoc_item(cx, item, ctxt); |
| run_early_pass!(cx, check_impl_item_post, item); |
| } |
| }); |
| } |
| |
| fn visit_lifetime(&mut self, lt: &'a ast::Lifetime) { |
| run_early_pass!(self, check_lifetime, lt); |
| self.check_id(lt.id); |
| } |
| |
| fn visit_path(&mut self, p: &'a ast::Path, id: ast::NodeId) { |
| run_early_pass!(self, check_path, p, id); |
| self.check_id(id); |
| ast_visit::walk_path(self, p); |
| } |
| |
| fn visit_attribute(&mut self, attr: &'a ast::Attribute) { |
| run_early_pass!(self, check_attribute, attr); |
| } |
| |
| fn visit_mac_def(&mut self, mac: &'a ast::MacroDef, id: ast::NodeId) { |
| run_early_pass!(self, check_mac_def, mac, id); |
| self.check_id(id); |
| } |
| |
| fn visit_mac(&mut self, mac: &'a ast::MacCall) { |
| // FIXME(#54110): So, this setup isn't really right. I think |
| // that (a) the librustc_ast visitor ought to be doing this as |
| // part of `walk_mac`, and (b) we should be calling |
| // `visit_path`, *but* that would require a `NodeId`, and I |
| // want to get #53686 fixed quickly. -nmatsakis |
| ast_visit::walk_path(self, &mac.path); |
| |
| run_early_pass!(self, check_mac, mac); |
| } |
| } |
| |
| struct EarlyLintPassObjects<'a> { |
| lints: &'a mut [EarlyLintPassObject], |
| } |
| |
| #[allow(rustc::lint_pass_impl_without_macro)] |
| impl LintPass for EarlyLintPassObjects<'_> { |
| fn name(&self) -> &'static str { |
| panic!() |
| } |
| } |
| |
| macro_rules! expand_early_lint_pass_impl_methods { |
| ([$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => ( |
| $(fn $name(&mut self, context: &EarlyContext<'_>, $($param: $arg),*) { |
| for obj in self.lints.iter_mut() { |
| obj.$name(context, $($param),*); |
| } |
| })* |
| ) |
| } |
| |
| macro_rules! early_lint_pass_impl { |
| ([], [$($methods:tt)*]) => ( |
| impl EarlyLintPass for EarlyLintPassObjects<'_> { |
| expand_early_lint_pass_impl_methods!([$($methods)*]); |
| } |
| ) |
| } |
| |
| crate::early_lint_methods!(early_lint_pass_impl, []); |
| |
| fn early_lint_crate<T: EarlyLintPass>( |
| sess: &Session, |
| lint_store: &LintStore, |
| krate: &ast::Crate, |
| pass: T, |
| buffered: LintBuffer, |
| warn_about_weird_lints: bool, |
| ) -> LintBuffer { |
| let mut cx = EarlyContextAndPass { |
| context: EarlyContext::new(sess, lint_store, krate, buffered, warn_about_weird_lints), |
| pass, |
| }; |
| |
| // Visit the whole crate. |
| cx.with_lint_attrs(ast::CRATE_NODE_ID, &krate.attrs, |cx| { |
| // since the root module isn't visited as an item (because it isn't an |
| // item), warn for it here. |
| run_early_pass!(cx, check_crate, krate); |
| |
| ast_visit::walk_crate(cx, krate); |
| |
| run_early_pass!(cx, check_crate_post, krate); |
| }); |
| cx.context.buffered |
| } |
| |
| pub fn check_ast_crate<T: EarlyLintPass>( |
| sess: &Session, |
| lint_store: &LintStore, |
| krate: &ast::Crate, |
| pre_expansion: bool, |
| lint_buffer: Option<LintBuffer>, |
| builtin_lints: T, |
| ) { |
| let passes = |
| if pre_expansion { &lint_store.pre_expansion_passes } else { &lint_store.early_passes }; |
| let mut passes: Vec<_> = passes.iter().map(|p| (p)()).collect(); |
| let mut buffered = lint_buffer.unwrap_or_default(); |
| |
| if !sess.opts.debugging_opts.no_interleave_lints { |
| buffered = |
| early_lint_crate(sess, lint_store, krate, builtin_lints, buffered, pre_expansion); |
| |
| if !passes.is_empty() { |
| buffered = early_lint_crate( |
| sess, |
| lint_store, |
| krate, |
| EarlyLintPassObjects { lints: &mut passes[..] }, |
| buffered, |
| pre_expansion, |
| ); |
| } |
| } else { |
| for pass in &mut passes { |
| buffered = |
| sess.prof.extra_verbose_generic_activity("run_lint", pass.name()).run(|| { |
| early_lint_crate( |
| sess, |
| lint_store, |
| krate, |
| EarlyLintPassObjects { lints: slice::from_mut(pass) }, |
| buffered, |
| pre_expansion, |
| ) |
| }); |
| } |
| } |
| |
| // All of the buffered lints should have been emitted at this point. |
| // If not, that means that we somehow buffered a lint for a node id |
| // that was not lint-checked (perhaps it doesn't exist?). This is a bug. |
| // |
| // Rustdoc runs everybody-loops before the early lints and removes |
| // function bodies, so it's totally possible for linted |
| // node ids to not exist (e.g., macros defined within functions for the |
| // unused_macro lint) anymore. So we only run this check |
| // when we're not in rustdoc mode. (see issue #47639) |
| if !sess.opts.actually_rustdoc { |
| for (_id, lints) in buffered.map { |
| for early_lint in lints { |
| sess.delay_span_bug(early_lint.span, "failed to process buffered lint here"); |
| } |
| } |
| } |
| } |
